Communication device and communication method

ABSTRACT

[Object] To provide a communication device and a communication method which are capable of achieving both an improvement in reliability of communication in which a frame is transmitted to a plurality of destinations and effective use of wireless communication resources. 
     [Solution] The communication device includes: a communication unit configured to perform communication of a frame. The communication unit transmits a transmission acknowledgment request frame for a transmission acknowledgment response frame including frequency allocation information specifying a transmission frequency of the transmission acknowledgment response frame, and receives the transmission acknowledgment response frame which has undergone frequency division multiplexing, on the basis of the frequency allocation information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/568,860, filed Oct. 24, 2017, which is based on PCT filingPCT/JP2016/062163, filed Apr. 15, 2016, and claims priority to JP2015-135956, filed Jul. 7, 2015, the entire contents of each areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to communication devices andcommunication methods.

BACKGROUND ART

In recent years, wireless local area networks (LANs) as typified by IEEE(Institute of Electrical and Electronics Engineers) 802.11 have beenwidespread. In addition, along with the widespread use of wireless LANs,products supporting the wireless LANs have been increasing.

On the other hand, techniques for efficiently communicating with aplurality of communication devices have been developed. As such atechnique, for example, a multicast scheme of transmitting frames to oneor more communication devices at a time is known.

Here, there are cases in which, in order to improve reliability ofcommunication, it is desirable to perform a transmission acknowledgmentfor frames (hereinafter also referred to as “acknowledgment (ACK)”) formulticast frames, similarly to unicast frames. As such transmissionacknowledgment, a Block ACK (BA) for transmission acknowledgment for aplurality of frames is known.

For example, the invention related to a wireless communication devicethat performs transmission of a Block Ack Request (BAR) frame indicatinga transmission request for a BA frame and reception of a BA frameserving as a response to the BAR frame for each terminal in order oftime after a multicast frame is transmitted to each terminal isdisclosed in Patent Literature 1.

CITATION LIST Patent Literature

Patent Literature 1: JP 2009-049704A

DISCLOSURE OF INVENTION Technical Problem

However, in the invention disclosed in Patent Literature 1, it isdifficult to efficiently use wireless communication resources. Forexample, wireless communication resources for transmissionacknowledgment for multicast frames are chronologically allocated toeach terminal serving as a transmission acknowledgment target. For thisreason, there are cases in which it is difficult to allocate wirelesscommunication resources to other communication until the transmissionacknowledgment for all terminals is completed.

Further, the above-mentioned problem is not limited to the multicastcommunication but may occur similarly even in other communication suchas frame multiplex communication in which a frame is transmitted to aplurality of destinations.

In this regard, the present disclosure proposes a communication deviceand a communication method which are novel and improved and capable ofachieving both an improvement in reliability of communication in which aframe is transmitted to a plurality of destinations and effective use ofwireless communication resources.

Solution to Problem

According to the present disclosure, there is provided a communicationdevice including: a communication unit configured to performcommunication of a frame. The communication unit transmits atransmission acknowledgment request frame for a transmissionacknowledgment response frame including frequency allocation informationspecifying a transmission frequency of the transmission acknowledgmentresponse frame, and receives the transmission acknowledgment responseframe which has undergone frequency division multiplexing, on the basisof the frequency allocation information.

In addition, according to the present disclosure, there is provided acommunication device including: a communication unit configured toperform communication of a frame. The communication unit receives atransmission acknowledgment request frame for a transmissionacknowledgment response frame including frequency allocation informationspecifying a transmission frequency of the transmission acknowledgmentresponse frame, and transmits the transmission acknowledgment responseframe on the basis of the frequency allocation information. Thetransmission acknowledgment response frame undergoes frequency divisionmultiplexing.

In addition, according to the present disclosure, there is provided acommunication method including: transmitting, by a communication unitconfigured to perform communication of a frame, a transmissionacknowledgment request frame for a transmission acknowledgment responseframe including frequency allocation information specifying atransmission frequency of the transmission acknowledgment responseframe; and receiving the transmission acknowledgment response framewhich has undergone frequency division multiplexing, on the basis of thefrequency allocation information.

In addition, according to the present disclosure, there is provided acommunication method including: receiving, by a communication unitconfigured to perform communication of a frame, a transmissionacknowledgment request frame for a transmission acknowledgment responseframe including frequency allocation information specifying atransmission frequency of the transmission acknowledgment responseframe; and transmitting the transmission acknowledgment response frameon the basis of the frequency allocation information. The transmissionacknowledgment response frame undergoes frequency division multiplexing.

Advantageous Effects of Invention

As described above, according to the present disclosure, a communicationdevice and a communication method which are capable of achieving both animprovement in reliability of communication in which a frame istransmitted to a plurality of destinations and effective use of wirelesscommunication resources are provided. Note that the effects describedabove are not necessarily limitative. With or in the place of the aboveeffects, there may be achieved any one of the effects described in thisspecification or other effects that may be grasped from thisspecification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration example of acommunication system according to an embodiment of the presentdisclosure.

FIG. 2 is a diagram for describing a transmission acknowledgment inmulticast communication of a related art.

FIG. 3 is a diagram illustrating a configuration example of an existingBAR frame.

FIG. 4 is a block diagram illustrating an example of a schematicfunctional configuration of each of an AP and an STA according to anembodiment of the present disclosure.

FIG. 5 is a diagram for describing an example of allocation of wirelesscommunication resources of an AP according to the present embodiment.

FIG. 6 is a diagram for describing another example of allocation ofwireless communication resources of an AP according to the presentembodiment.

FIG. 7 is a diagram illustrating a configuration example of atransmission acknowledgment request frame transmitted by an AP accordingto the present embodiment.

FIG. 8 is a flowchart conceptually illustrating a process of an APaccording to the present embodiment.

FIG. 9 is a flowchart conceptually illustrating a process of an STAaccording to the present embodiment.

FIG. 10 is a diagram for describing an example of allocation of wirelesscommunication resources of an AP according to a first modified exampleof the present embodiment.

FIG. 11 is a diagram for describing an example of allocation of wirelesscommunication resources of an AP according to a second modified exampleof the present embodiment.

FIG. 12 is a block diagram illustrating an example of a schematicconfiguration of a smartphone.

FIG. 13 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device.

FIG. 14 is a block diagram illustrating an example of a schematicconfiguration of a wireless access point.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. In thisspecification and the appended drawings, structural elements that havesubstantially the same function and structure are denoted with the samereference numerals, and repeated explanation of these structuralelements is omitted.

Further, in this specification and the drawings, there are cases inwhich a plurality of structural elements having substantially the samefunction are distinguished by adding different numbers to the end of thesame reference numeral. For example, a plurality of structural elementshaving substantially the same function are distinguished as necessarylike an STA 20#1 and an STA 20#2. However, in a case where it isunnecessary to distinguish structural elements having substantially thesame function, only the same reference numeral is added. For example, ina case where it is unnecessary to particularly distinguish the STA 20#1and the STA 20#2, they are simply referred to as “STAs 20.”

Note that, the description is given in the following order.

1. Overview of communication device according to embodiment of presentdisclosure2. Communication device according to embodiment of present disclosure2-1. Configuration of device2-2. Technical feature2-3. Process performed by device

2-4. Modification

3. Application example

4. Conclusion 1. OVERVIEW OF COMMUNICATION SYSTEM ACCORDING TOEMBODIMENT OF PRESENT DISCLOSURE

First, with reference to FIG. 1, an overview of a communication systemaccording to an embodiment of the present disclosure will be described.FIG. 1 is a diagram illustrating a configuration example of acommunication system according to the embodiment of the presentdisclosure.

The communication system is configured with a communication device 10and a plurality of communication devices 20. Each of the communicationdevice 10 and the communication device 20 has a wireless communicationfunction. Particularly, the communication device 10 has a multicastcommunication function of transmitting frames to one or morecommunication devices. Further, the communication device 10 operates asan access point (hereinafter, also referred to as an “access point(AP)”), and the communication device 20 operates as a station(hereinafter also referred to as a “station (STA)”). Hereinafter, thecommunication device 10 is also referred to as an “AP 10,” and thecommunication device 20 is also referred to as an “STA 20.” For thisreason, in the communication system, the multicast communication fromthe AP 10 to a plurality of STAs 20 can be performed. Further,communication from the AP 10 to the STA 20 is referred to as a “downlink(DL),” and communication from the STA 20 to the AP 10 is also referredto as an “uplink (UL).”

For example, as illustrated in FIG. 1, the communication system may beconfigured with the AP 10 and a plurality of STAs 20#1 to 20#4. The AP10 and the STAs 20#1 to 20#4 are connected to each other via wirelesscommunication and perform transmission and reception of frames directlywith each other. For example, the AP 10 is a communication deviceconforming to IEEE 802.11 and transmits a multicast frame having each ofthe STAs 20#1 to 20#4 as a destination.

Here, the transmission acknowledgment for the multicast frame isconsidered to be performed in order to improve the reliability of themulticast communication. Specifically, the BAR frame and the BA frame(hereinafter also referred to as a “transmission acknowledgment frame”)are exchanged as the transmission acknowledgment for the multicast frameafter the multicast frame is transmitted. A transmission acknowledgmentin multicast communication of a related art will be described withreference to FIG. 2. FIG. 2 is a diagram for describing a transmissionacknowledgment in a multicast communication of a related art.

The wireless communication resources for transmission of thetransmission acknowledgment frame for the multicast frame arechronologically allocated to each STA of the transmission acknowledgmenttarget. For example, wireless communication resources for transmissionof BAR#1 to BAR#4 frames and BA#1 to BA#4 frames to STAs #1 to #4 aresequentially allocated along a time axis as illustrated in FIG. 2.

Next, multicast communication of the related art and a communicationform for the transmission acknowledgment will be described.

First, after the multicast frame is transmitted to each of the STAs, theAP transmits the BAR frame to each of the STAs in order of time. Forexample, after the multicast frame is transmitted, the AP transmits theBAR#1 to BAR#4 frames illustrated in FIG. 2 to each of the STAs #1 to #4in order of time.

Further, each STA transmits the BA frame to the AP when the BAR frame isreceived. For example, each of STAs #1 to #4 transmits the BA#1 to BA#4frames illustrated in FIG. 2 to the AP when the BAR#1 to BAR#4 framesare received.

As described above, in the transmission acknowledgment in the multicastcommunication of the related art, the wireless communication resourcesfor the transmission acknowledgment are chronologically allocated toeach of the STAs. For this reason, there are cases in which it isdifficult to allocate wireless communication resources to othercommunication until the transmission acknowledgment for all terminals iscompleted. Further, the above-mentioned problem is not limited to themulticast communication but may occur similarly even in othercommunication such as frame multiplex communication in which a frame istransmitted to a plurality of destinations.

Further, in a case in which data for the transmission acknowledgment issmaller in an amount than data transmitted through a frame which is atransmission acknowledgment target, the wireless communication resourcesmay be wasted. The waste of the wireless communication resources in thecommunication for the transmission acknowledgment will be described indetail with reference to FIG. 3. FIG. 3 is a diagram illustrating aconfiguration example of an existing BAR frame.

Here, the communication for the transmission acknowledgment is generallyperformed using substantially the same bandwidth as a bandwidth used forthe transmission of the frame which is the transmission acknowledgmenttarget. For example, the BAR frame and the BA frame are transmittedthrough the same bandwidth as the bandwidth used for transmission of themulticast frame.

On the other hand, the data size of the transmission acknowledgment isoften smaller than the data size of the data frame. For example, asillustrated in FIG. 3, the BAR frame includes a physical layer header(PHY Header), a media access control header (MAC Header), BA Control, BAInfo, and a frame check sequence (FCS). The data size of the BAR frameis at most 152 octets (bytes) as illustrated in FIG. 3, but the datasize of the data frame is usually larger than 152 octets (bytes). Forthis reason, in this case, an excessive bandwidth is allocated to thecommunication for the transmission acknowledgment.

In this regard, the present disclosure proposes a communication devicewhich is capable of achieving both an improvement in reliability ofcommunication in which a frame is transmitted to a plurality ofdestinations and effective use of wireless communication resources.Next, details thereof will be described. Note that, FIG. 1 illustratesthe communication system including the AP 10 and the STAs 20 as anexample of the communication system. One of the STAs 20 may be acommunication device that establishes a plurality of direct links withother STAs 20 instead of the AP 10. In that case, DL can be replacedwith “simultaneous transmission from one STA to a plurality of STAs,”and UL can be replaced with “simultaneous transmission from a pluralityof STAs to one STA.”

2. COMMUNICATION DEVICE ACCORDING TO EMBODIMENT OF PRESENT DISCLOSURE

As described above, the overview of the communication system accordingto the embodiment of the present disclosure has been described. Next,the AP 10 and the STAs 20 according to the embodiments of the presentdisclosure will be described. An example in which the BAR frame and theBA frame are exchanged as a transmission acknowledgment request frameand a transmission acknowledgment response frame will be describedbelow.

2-1. Configuration of Device

First, with reference to FIG. 4, a basic functional configuration ofeach of the AP 10 and the STA 20 according to the embodiment of thepresent disclosure will be described. FIG. 4 is a block diagramillustrating an example of a schematic functional configuration of eachof the AP and the STA 20 according to the embodiment of the presentdisclosure.

As illustrated in FIG. 4, each of the AP 10 and the STA 20 includes adata processing unit 11, a wireless communication unit 12, a controlunit 13, and a storage unit 14.

As a part of a communication unit, the data processing unit 11 performsa process on data for transmission and reception. Specifically, the dataprocessing unit 11 generates a frame on the basis of data from a higherlayer of communication, and provides the generated frame to the wirelesscommunication unit 12. For example, the data processing unit 11generates a frame (or a packet) from the data, and performs a process onthe generated frame such as addition of a MAC header for media accesscontrol (MAC), addition of an error detection code, or the like. Inaddition, the data processing unit 11 extracts data from the receivedframe, and provides the extracted data to the higher layer ofcommunication. For example, the data processing unit 11 acquires data byanalyzing a MAC header, detecting and correcting a code error, andperforming a reorder process, or the like with regard to the receivedframe.

The wireless communication unit 12 has a signal processing function, awireless interface function, and the like as part of a communicationunit.

The signal processing function is a function of performing signalprocessing such as modulation on frames. Specifically, the wirelesscommunication unit 12 performs encoding, interleaving, and modulation onthe frame provided from the data processing unit 11 in accordance with acoding and modulation scheme set by the control unit 13, adds a preambleand a PHY header, and generates a symbol stream. Further, the wirelesscommunication unit 12 acquires a frame by performing demodulation,decoding, and the like on the symbol stream obtained by a process of thewireless interface function, and provides the obtained frame to the dataprocessing unit 11 or the control unit 13.

The wireless interface function is a function to transmit/receive asignal via an antenna. Specifically, the wireless communication unit 12converts a signal related to the symbol stream obtained through theprocess performed by the signal processing function into an analogsignal, amplifies the signal, filters the signal, and up-converts thefrequency. Next, the the wireless communication unit 12 transmits theprocessed signal via the antenna. In addition, on the signal obtainedvia the antenna, the wireless communication unit 12 performs a processthat is opposite to the process at the time of signal transmission suchas down-conversion in frequency or digital signal conversion.

As a part of the communication unit, the control unit 13 controls entireoperation of the AP 10 or the STA 20. Specifically, the control unit 13performs a process such as exchange of information between functions,setting of communication parameters, or scheduling of frames (orpackets) in the data processing unit 11.

The storage unit 14 stores information to be used for process to beperformed by the data processing unit 11 or the control unit 13.Specifically, the storage unit 14 stores information stored in atransmission frame, information acquired from a receiving frame,information on a communication parameter, or the like.

2-2. Technical Feature

Next, characteristic functions of the AP 10 and the STA 20 according toone embodiment of the present disclosure will be described.

((Functions of AP))

First, the characteristic functions of the AP 10 will be described.

(Transmission of Multicast Frame)

The AP 10 transmits the multicast frame to the STA 20. Specifically, thecontrol unit 13 causes the data processing unit 11 to generate amulticast frame whose destination is one or a plurality of STAs 20, andthe wireless communication unit 12 transmits the generated multicastframe. For example, the multicast frame may be a data frame. Themulticast frame may be a control frame or a management frame.

(Decision of Transmission Acknowledgment Target)

The AP 10 decides the STA 20 which is the transmission acknowledgmenttarget for the multicast frame. Specifically, the control unit 13decides the number of STAs 20 serving as the transmission acknowledgmenttarget, and selects the decided number or less f STAs 20 as thetransmission acknowledgment target from the STAs 20 which are thedestination of the multicast frame.

More specifically, the control unit 13 decides the number of STAs 20serving as the transmission acknowledgment target on the basis of acongestion degree of the communication. For example, the control unit 13decides the number of STAs 20 serving as the transmission acknowledgmenttarget in accordance with an amount of available wireless communicationresources. The control unit 13 may decide the number of the STAs 20serving as the transmission acknowledgment target on the basis of apredetermined value. For example, the predetermined value is stored inthe storage unit 14.

Further, the control unit 13 selects the STA 20 serving as thetransmission acknowledgment target from the STAs 20 which are thedestination of the multicast frame on the basis of a receptioncharacteristic of the STA 20. For example, the reception characteristicof the STA 20 includes at least one of a symbol error rate, a signal tonoise ratio (SN ratio), a communication throughput, and the number ofmulticast frames successfully received by the STA 20. Then, the controlunit 13 preferentially selects the STA 20 having a lower receptioncharacteristic, for example, a lower SN ratio as the transmissionacknowledgment target. In this case, since the STA 20 having thecommunication reliability lower than other STAs 20 is selected as thetransmission acknowledgment target, it is possible to effectivelyimprove the reliability of the entire multicast communication.

As described above, the AP 10 decides the number of STAs 20 serving asthe transmission acknowledgment target, and selects the decided numberor less of STAs 20 as the transmission acknowledgment target from theSTAs 20 which are the destination of the multicast frame. Therefore, theradio transmission resources for the transmission acknowledgment aresuppressed from being tightened since the number of STAs 20 serving asthe destination of the multicast frame is increased. As a result, it ispossible to perform the transmission acknowledgment for the multicastframe having the good efficiency.

(Allocation of Wireless Communication Resources for TransmissionAcknowledgment)

The AP 10 allocates the wireless communication resources for thetransmission acknowledgment to each of the STAs 20 decided as thetransmission acknowledgment target. Specifically, the control unit 13decides a center frequency and a bandwidth used in the transmissionacknowledgment response as a transmission frequency for each of the STAs20 of the transmission acknowledgment target. The allocation of thewireless communication resources will be described in detail withreference to FIGS. 5 and 6. FIG. 5 is a diagram for describing anexample of the allocation of the wireless communication resources of theAP 10 according to the present embodiment and FIG. 6 is a diagram fordescribing another example of the allocation of the wirelesscommunication resources of the AP 10 according to the presentembodiment.

The control unit 13 decides the center frequency to be allocated to eachof the STAs 20 selected as the destination of the BAR frame transmittedin the same period, that is, the transmission acknowledgment target asthe center frequency differing for each STA 20. For example, asillustrated in FIG. 5, the wireless communication resources areallocated to BA#1 to BA#4 frames in the same period, but the centerfrequencies of the allocated wireless communication resources aredifferent from each other. The center frequencies of the wirelesscommunication resources allocated in different periods may be the same.

Here, the wireless communication resources may be allocated biased to aspecific band, depending on a center frequency decision method. Further,there are also cases where the band to which the wireless communicationresources are unevenly allocated is crowded. In this case, thecommunication efficiency in the transmission acknowledgment response maydecrease.

In this regard, the AP 10 distributes the band used for the transmissionof the transmission acknowledgment response frame to the STAs 20selected as the transmission acknowledgment target. Specifically, thecontrol unit 13 decides the center frequency on the basis of at leastone of identification information of the selected STA 20 and timeinformation of the AP 10.

For example, the identification information is a connection identifiersuch as an association identifier (AID), and the time information is atime stamp obtained using a time synchronization function (TSF) or thelike (hereinafter also referred to as “TSFv”). Then, the control unit 13decides the center frequency using the following Formula.

[Math. 1]

Ch=mod[(TSFv+AID),CH_NUM]  (1)

In Formula (1), Ch indicates an index indicating a channel number, thatis, the center frequency, and CH_NUM indicates the number of channelsavailable for the transmission acknowledgment. The center frequency isuniquely specified from Ch. Further, since TSFv has a fine grain size,it is desirable that TSFv rounded to the extent that there is no errorbetween AP 10 and STA 20 is used.

The control unit 13 may decide the center frequency to be allocated as acenter frequency that is different from the center frequency of themulticast frame. For example, as illustrated in FIG. 5, the centerfrequency to be allocated to the BA#1 to BA#4 frames is different fromthe center frequency to be allocated to the multicast frame. Of course,the center frequency of the wireless communication resources for thetransmission acknowledgment may be the same as the center frequencyallocated to the multicast frame.

Further, the control unit 13 decides a bandwidth allocated to each ofthe STAs 20 selected as the destination of the BAR frame, that is, thetransmission acknowledgment target as a different bandwidth among atleast some of the STAs 20. Specifically, the control unit 13 decides abandwidth of a certain STA 20 on the basis of whether or not a centerfrequency adjacent to the center frequency allocated to the certain STA20 is allocated to other STAs 20.

Here, in IEEE 802.11, the BAR frame is supposed to be transmittedthrough a bandwidth of 20 MHz, that is, one channel. Therefore, whenavailable bandwidths are two or more channels, it is possible totransmit the same BAR frame using the bandwidth of the two or morechannels. As a result, in a communication device serving as a receptionside, that is, the STA 20, it is desirable to successfully receive atleast one of a plurality of BAR frames, and thus a frequency diversityeffect is obtained, and it is possible to improve the reliability of thecommunication for the transmission acknowledgment response.

For example, as illustrated in FIG. 6, since the center frequencyadjacent to the center frequency of the BA#2 frame is not allocated toanother STA 20, that is, since the transmission acknowledgment for otherSTAs 20 is not performed using the adjacent center frequency, a widerbandwidth than the bandwidth of the BA#1 frame is allocated to the BA#2frame. Of course, the same bandwidth may be allocated to each of theSTAs 20. For example, as illustrated in FIG. 5, the same bandwidth isallocated to the BA#1 to BA#4 frames.

Further, the bandwidth need not be necessarily expanded even when theadjacent center frequency is not allocated to other STAs 20. Forexample, as illustrated in FIG. 6, although the center frequencyadjacent to the center frequency of the BA#1 frame is empty, thebandwidth of the BA#1 is not expanded.

Further, in addition to the presence or absence of the allocation of theadjacent center frequency to other STAs 20, other conditions may be usedfor the decision of the bandwidth. For example, the control unit 13decides the bandwidth on the basis of the presence or absence ofallocation of the adjacent center frequency to the other STAs 20 and thereception characteristic of the STA 20.

Further, the control unit 13 may decide a bandwidth used for thetransmission of the transmission acknowledgment response frame in thesame period as the bandwidth different from the bandwidth of themulticast frame. For example, as illustrated in FIG. 6, a sum ofbandwidths allocated to the BA#1 to BA#2 frames transmitted in the sameperiod is narrower than the bandwidth allocated to the multicast frame.Further, a sum of the bandwidths allocated to the BA frames may be thesame as the bandwidth allocated to the multicast frame or may be widerthan the bandwidth allocated to the multicast frame.

Further, the control unit 13 may decide the bandwidth allocated to eachof the STAs 20 as the bandwidth different from the bandwidth of themulticast frame. For example, as illustrated in FIG. 5, the bandwidthsallocated to the BA#1 to BA#4 frames are narrower than the bandwidthallocated to the multicast frame. Of course, the bandwidth of thewireless communication resources for the transmission acknowledgment maybe the same as the bandwidth allocated to the multicast frame or may bewider than the bandwidth allocated to the multicast frame.

(Transmission of Transmission Acknowledgment Request Frame)

The AP 10 transmits the transmission acknowledgment request frame forthe transmission acknowledgment response frame including informationspecifying the transmission frequency of the transmission acknowledgmentresponse frame (hereinafter also referred to as “frequency allocationinformation”). Specifically, the control unit 13 causes the dataprocessing unit 11 to generate a BAR frame including the frequencyallocation information specifying the transmission frequency of the BAframe for the multicast frame. Then, the wireless communication unit 12transmits the generated BAR frame. For example, a BAR frame (aMulti-Channel BAR (MBAR)) for the multicast frame illustrated in FIG. 5is transmitted to each of STAs 20 belonging to a multicast group (forexample, a group A) that is the destination of the multicast frame. TheMBAR frame according to the present embodiment will be described indetail with reference to FIG. 7. FIG. 7 is a diagram illustrating aconfiguration example of the MBAR frame transmitted by the AP 10according to the present embodiment.

First, an overall configuration of the MBAR frame will be described. Forexample, as illustrated in an upper part of FIG. 7, the MBAR frameincludes a PHY Header, a MAC Header, and BAR information of each STA 20of the transmission acknowledgment target (hereinafter also referred toas simply “BAR information”) and an FCS. A multicast group ID of atransmitted multicast frame is stored in a receiver address (RA) fieldof the MAC Header serving as the destination information of the MBARframe. Further, only the STA 20 of the transmission acknowledgmenttarget may be stored as the destination information of the MBAR frame.

Next, the BAR information field for each STA 20 of the transmissionacknowledgment target will be described. For example, as illustrated inthe upper part of FIG. 7, the BAR information field of each STA 20 ofthe transmission acknowledgment target includes fields such as STA IDand BA Control each serving as a field in which response deviceinformation is stored and Channel Info serving as a filed in which thefrequency allocation information is stored.

Further, the Channel Info field will be described. For example, asillustrated in a lower part of FIG. 7, the Channel Info field includesfields such as Center Frequency and Channel Width.

Information specifying the center frequency of the transmissionfrequency for the transmission acknowledgment response frame serving asthe frequency allocation information (hereinafter also referred to as“primary channel information”) is stored in the Center Frequency field.For example, the primary channel information is information indicatingthe center frequency decided for each of the STAs 20 individually.

Information specifying the bandwidth of the transmission frequency forthe transmission acknowledgment response frame serving as the frequencyallocation information (hereinafter also referred to as “bandwidthinformation”) is stored in the Channel Width field. For example, thebandwidth information is information indicating the bandwidth decidedfor each of the STAs 20 individually.

The example in which Channel Info is set for each STA 20 of thetransmission acknowledgment target has been described, but singleChannel Info common to the STAs 20 may be set. Specifically, informationrelated to a calculation formula for calculating the center frequency isstored in the Center Frequency field. For example, the primary channelinformation includes information indicating Formula (1), informationindicating TSFv in Formula (1), and information indicating CH_NUM.Furthermore, the primary channel information may include only theinformation indicating TSFv in a case in which Formula (1) and CH_NUMare known to the STA 20. In this case, the STA 20 calculates thebandwidth of the STA 20 by applying the AID of the STA 20 and TSFvincluded in the primary channel information to Formula (1). Accordingly,the data amount of the MBAR frame is reduced as compared with the casewhere the primary channel information of each STA 20 is stored, and itis possible to effectively use the wireless communication resources.

Further, information indicating the maximum bandwidth and the minimumbandwidth among the bandwidths allocated to the selected STAs 20 isstored in the Channel Width field. For example, the STA 20 transmits theBA frame using any one of the minimum bandwidth and the maximumbandwidth stored in the bandwidth information. In this case, the dataamount of the MBAR frame is reduced as compared with the case in whichthe bandwidth information of each STA 20 is stored, and it is possibleto effectively use the wireless communication resources.

Further, only one of the Center Frequency field and the Channel Widthfield may be a field for storing one piece of information common to theSTAs 20 of the transmission acknowledgment target described above.

(Reception of Transmission Acknowledgment Response Frame)

The AP 10 receives the transmission acknowledgment response frame whichhas undergone the frequency division multiplexing on the basis of thefrequency allocation information. Specifically, the wirelesscommunication unit 12 receives the BA frame which has undergone thefrequency division multiplexing and been transmitted through thetransmission frequency specified by the frequency allocation informationnotified to the STA 20 through the MBAR frame. For example, after theBAR frame is transmitted, the wireless communication unit 12 receives aBA frame group which has undergone the frequency division multiplexingas a response to the BAR frame, and acquires the BA frame of each of theSTAs 20 from the BA frame group on the basis of the center frequency andthe bandwidth notified to each of the STAs 20 of the transmissionacknowledgment target through the BAR frame. The transmissionacknowledgment response frame is received only from the STA 20 specifiedfrom the response device information included in the transmissionacknowledgment request frame.

((Functions of STA))

Next, the characteristic functions of the STA 20 will be described.

(Reception of Multicast Frame)

The STA 20 receives the multicast frame from the AP 10. The control unit13 sets a communication frequency of the STA 20 to the center frequencyand the bandwidth at which the multicast frame is received successfullyin advance.

(Reception of Transmission Acknowledgment Request Frame)

The STA 20 receives the transmission acknowledgment request frameincluding the frequency allocation information from the AP 10.Specifically, the wireless communication unit 12 receives the MBAR framefrom the AP 10 after receiving the multicast frame. If the MBAR frame isreceived by the wireless communication unit 12, in a case in which theSTA 20 belongs to the multicast group which is the destination of theMBAR frame, the data processing unit 11 acquires the BAR informationmatching the STA ID of the STA 20 from the MBAR frame.

(Setting of Transmission Frequency)

If the transmission acknowledgment request frame including the frequencyallocation information is received, the STA 20 sets the transmissionfrequency of the STA 20 as the transmission frequency for transmittingthe transmission acknowledgment response frame. Specifically, thecontrol unit 13 sets the transmission frequency specified from thefrequency allocation information included in the BAR informationacquired by the data processing unit 11. For example, the control unit13 sets the transmission frequency of the STA 20 to the center frequencyand the bandwidth respectively specified from the primary channelinformation and the bandwidth information included in the MBAR frame.

In a case in which only information for calculating the center frequencyand the bandwidth is included in the MBAR frame as described above, thecontrol unit 13 calculates the center frequency and the bandwidth on thebasis of the primary channel information and the bandwidth information.

(Transmission of Transmission Acknowledgment Response Frame)

The STA 20 transmits the transmission acknowledgment response frame forthe received transmission acknowledgment request frame on the basis ofthe frequency allocation information included in the transmissionacknowledgment request frame. Specifically, after the MBAR frame isreceived, the wireless communication unit 12 transmits the BA frameusing the transmission frequency specified from the frequency allocationinformation included in the MBAR frame. For example, in a case in whichthe BAR information matching the STA ID of the STA 20 is included in thereceived MBAR frame, the control unit 13 causes the data processing unit11 to generate the BA frame as the response to the MBAR frame. Then, thewireless communication unit 12 transmits the generated BA frame to theAP 10 through the center frequency and the bandwidth set on the basis ofthe frequency allocation information included in the acquired BARinformation. As a result, the BA frame transmitted from the STA 20undergoes the frequency division multiplexing, and the BA frame groupwhich has undergone the frequency division multiplexing is received bythe AP 10.

2-3. Process of Device

Next, a process of the AP 10 and the STA 20 according to the presentembodiment will be described.

(Process of AP)

First, the process of the AP 10 according to the present embodiment willbe described with reference to FIG. 8. FIG. 8 is a flowchartconceptually illustrating the process of the AP 10 according to thepresent embodiment.

The AP 10 transmits the multicast frame to each of the STAs 20 (stepS102). Specifically, the control unit 13 causes the data processing unit11 to generate the multicast frame whose destination is each of the STAs20. Then, the wireless communication unit 12 transmits the generatedmulticast frame.

Next, the AP 10 transmits the BAR frame to each of the STAs 20 (stepS104). Specifically, the control unit 13 generates the MBAR frameincluding the frequency allocation information for the STA 20 of thetransmission acknowledgment target in which the multicast group of themulticast frame transmitted to the data processing unit 11 is thedestination. Then, the wireless communication unit 12 transmits thegenerated MBAR frame. Further, the MBAR frame may be aggregated with themulticast frame.

Then, the AP 10 configures a reception setting on the basis of thetransmission frequency of the BA frame (step S106). Specifically, thecontrol unit 13 causes the wireless communication unit 12 to set areception frequency so that the BA frame transmitted through the centerfrequency and the bandwidth specified on the basis of the frequencyallocation information included in the MBAR frame is received.

Then, the AP 10 determines whether or not the BA frame is received (stepS108). Specifically, after the MBAR frame is transmitted, the controlunit 13 determines whether or not the BA frame serving as the responseto the MBAR frame is received from each of the STAs 20 of thetransmission acknowledgment target. In a case in which the BA frame isdetermined not to be received from the STA 20 of the transmissionacknowledgment target, the control unit 13 causes the wirelesscommunication unit 12 to retransmit the BAR frame or the MBAR frame forthe BA frame which is not yet received. In a case in which the BA frameis not received within a predetermined period of time, the process mayreturn to step S102, and the multicast frame or the data frame may beretransmitted to the STA 20 that has not received the BA frame.

(Process of STA)

Next, a process of the STA 20 according to the present embodiment willbe described with reference to FIG. 9. FIG. 8 is a flowchartconceptually illustrating the process of the STA 20 according to thepresent embodiment.

The STA 20 receives the multicast frame from the AP 10 (step S202).Specifically, the wireless communication unit 12 receives the multicastframe from the AP 10.

Then, the STA 20 receives the BAR frame from the AP 10 (step S204).Specifically, the wireless communication unit 12 receives the MBAR frameafter receiving the multicast frame. If the MBAR frame is received, thecontrol unit 13 acquires the BAR information matching the STA ID of theSTA 20 in a case in which the STA 20 belongs to the multicast groupwhich is the destination of the MBAR frame. In a case in which the STA20 does not belong to the multicast group or in a case in which there isno BAR information matching the STA ID of the STA 20, the process ends.

If the BAR frame is received, the STA 20 sets a designated transmissionfrequency as the transmission frequency of the STA 20 (step S206).Specifically, the control unit 13 sets the transmission frequency of theSTA 20 on the basis of the primary channel information and the bandwidthinformation included in the BAR information acquired from the receivedMBAR frame.

Then, the STA 20 transmits the BA frame to the AP 10 (step S208).Specifically, the control unit 13 causes the data processing unit 11 togenerate the BA frame serving as the response to the MBAR frame. Then,the wireless communication unit 12 transmits the generated BA frame tothe AP 10 through the set transmission frequency.

2-4. Conclusion of Embodiment of Present Disclosure

As described above, according to one embodiment of the presentdisclosure, the AP 10 transmits the transmission acknowledgment requestframe for the transmission acknowledgment response frame including thefrequency allocation information specifying the transmission frequencyof the transmission acknowledgment response frame, and receives thetransmission acknowledgment response frame which has undergone thefrequency division multiplexing on the basis of the frequency allocationinformation. Further, the STA 20 receives the transmissionacknowledgment request frame and transmits the transmissionacknowledgment response frame on the basis of the frequency allocationinformation. As a result, the transmission acknowledgment response frameundergoes the frequency division multiplexing. Thus, the transmissionacknowledgment response related to the communication in which a frame istransmitted to a plurality of destinations is performed using thefrequency division multiplex communication, and thus it is possible toeffectively use the wireless communication resources while improving thereliability of the communication as compared with the case in which thecommunication for the transmission acknowledgment response ischronologically performed.

Further, the transmission acknowledgment response frame is transmittedby the STA 20 through the transmission frequency specified from thefrequency allocation information. Therefore, the reliability of thetransmission acknowledgment response frame being received by the AP 10can be improved, and the communication efficacy can be improved.

Further, the transmission acknowledgment response frame includes thetransmission acknowledgment response frame for the multicast frame.Therefore, it is possible to effectively use the wireless communicationresources while improving the reliability of the multicastcommunication.

Further, the transmission acknowledgment request frame may beconcatenated to the frame which is the transmission acknowledgmenttarget. Therefore, since the standby time from the transmission of themulticast frame to the transmission of the transmission acknowledgmentrequest frame is saved, it is possible to reduce the time taken for thetransmission acknowledgment, that is, to reduce the wirelesscommunication resources used for the transmission acknowledgment.

The transmission acknowledgment request frame includes the responsedevice information specifying the communication device which isrequested to transmit the transmission acknowledgment response frame,and the AP 10 receives the transmission acknowledgment response framefrom the communication device specified on the basis of the responsedevice information. Further, in a case in which the STA 20 is thecommunication device specified from the response device information, theSTA 20 transmits the transmission acknowledgment response frame.Therefore, since the transmission acknowledgment response frame istransmitted to only a desired communication device, it is possible tofurther effectively use the wireless communication resources.

Further, the frequency allocation information includes the informationspecifying the center frequency of the transmission frequency.Therefore, since the notification of the center frequency is given tothe STA 20 through the frame, the AP 10 is able to dynamically allocatethe center frequency and perform the transmission acknowledgmentresponse suitable for a communication environment, the state of the STA20 or the like.

Further, the center frequency differs for each destination of thetransmission acknowledgment request frame transmitted during the sameperiod. Thus, since a collision of frames or interference of signals isprevented in the transmission acknowledgment response performed usingthe center frequency, it is possible to perform the efficientcommunication in the transmission acknowledgment response.

Further, the center frequency is specified on the basis of at least oneof the identification information for the destination of thetransmission acknowledgment request frame and the time information onits own device. Therefore, it is possible to suppress the centerfrequency from being allocated biased to the congested band.

Further, the frequency allocation information includes the informationspecifying the bandwidth of the transmission frequency. Therefore, sincethe notification of the bandwidth is given to the STA 20 through theframe, the AP 10 is able to dynamically allocate the bandwidth andperform the transmission acknowledgment response suitable for thecommunication environment or the state of the STA 20.

Further, the bandwidth is different between at least some of thedestinations of the transmission acknowledgment request frame.Therefore, since the bandwidth suitable for each of the STAs 20 isallocated, it is possible to efficiently use the bandwidth in thetransmission acknowledgment response of the STA 20 and improve thecommunication efficiency.

Further, the center frequency is different from the center frequency ofthe frame which is the transmission acknowledgment target. Further, thebandwidth used for the transmission of the transmission acknowledgmentresponse frame in the same period is different from the bandwidth of theframe which is the transmission acknowledgment target. Therefore, thedegree of freedom for the allocation of the wireless communicationresources for the transmission acknowledgment response is increased, andit is possible to improve the efficiency of transmission acknowledgmentresponse.

2-5. Modified Examples

One embodiment of the present disclosure has been described above. Thepresent embodiment is not limited to the above example. First and secondmodified examples of the present embodiment will be described below.

First Modified Example

As the first modified example of the present embodiment, thetransmission acknowledgment response frame may undergo time division.Specifically, the transmission acknowledgment request frame furtherincludes transmission time information specifying a transmission time(transmission timing) of the transmission acknowledgment response frame.For example, a transmission time field in which the transmission timeinformation is stored is included in the Channel Info field of the MBARframe as illustrated in FIG. 7. For example, the transmission timeinformation may be information indicating a standby time inter framespace (IFS) from reception of the multicast frame or the MBAR frame butmay be information indicating the transmission time. A process accordingto the present modified example will be described in detail withreference to FIG. 10. FIG. 10 is a diagram for describing an example ofallocation of wireless communication resources of the AP 10 inaccordance with the first modified example of the present embodiment.

The AP 10 decides the presence or absence of time division of thetransmission acknowledgment response frame in accordance with the degreeof congestion of the communication of the transmission acknowledgmentresponse frame. Specifically, the AP 10 decides the presence or absenceof the time division on the basis of the available bandwidth and thenumber of STAs 20 of the transmission acknowledgment target. Forexample, in a case in which the number of STAs 20 that can be allocatedto the available bandwidth is equal to or larger than the number of STAs20 of the transmission acknowledgment target, the control unit 13decides that the time division multiplexing is performed on thetransmission acknowledgment response frame. The presence or absence ofthe time division multiplexing may be decided on the basis of acomparison between the number of STAs 20 of the transmissionacknowledgment target and a predetermined threshold value. Further, inthe transmission acknowledgment response frame, a communication ordermay be decided chronologically instead of multiplexing.

Then, in a case in which the time division multiplexing is performed onthe transmission acknowledgment response frame, the AP 10 decides thetransmission time information so that the time division multiplexing isperformed on the transmission acknowledgment response frame. Forexample, as illustrated in FIG. 10, the control unit 13 allocates atransmission period subsequent to the transmission of the MBAR frame forthe BA#1 and BA#2 frames, and allocates a next transmission periodsubsequent to the transmission period of the BA#1 and BA#2 frames forthe BA#3 and BA#4 frames. Then, the control unit 13 decides thetransmission time so that each transmission acknowledgment responseframe is transmitted in the transmission period.

Then, the AP 10 transmits the transmission acknowledgment request frameincluding the frequency allocation information and the transmissionperiod information. For example, the data processing unit 11 generatesan MBAR frame in which the decided each transmission time is stored inthe BAR information for each STA 20 of the transmission acknowledgmenttarget, that is, the transmission time field of the Channel Info field.Then, the generated MBAR frame is transmitted by the wirelesscommunication unit 12. Further, in a case in which the time divisionmultiplexing is not performed, a transmission acknowledgment requestframe in which the transmission time information is not stored in thetransmission period field may be transmitted, or a transmissionacknowledgment request frame with no transmission period field may betransmitted.

The STA 20 that has received the transmission acknowledgment requestframe transmits the transmission acknowledgment response frame in thetransmission period allocated to the STA 20. For example, if the MBAR isreceived, the STAs 20#1 and 20#2 transmit the BA#1 and BA#2 frames at atiming which is temporally adjacent to the transmission of the MBARframe as illustrated in FIG. 10. Further, after the MBAR is received,the STAs 20#3 and 20#4 transmit the BA#3 and BA#4 frames at a timingwhich is temporally adjacent to the transmission of the BA#1 and BA#2frames as illustrated in FIG. 10. As a result, the time divisionmultiplexing is performed on the BA#1 and BA#2 frames and the BA#3 andBA#4 frames.

As described above, according to the first modified example of thepresent embodiment, the transmission acknowledgment request framefurther includes the transmission time information specifying thetransmission time of the transmission acknowledgment response frame, andthe transmission acknowledgment response frame is transmitted at thetransmission time specified from the transmission time information andundergoes the time division. Therefore, it is possible to set more STAs20 as the transmission acknowledgment target, and it is possible toimprove the reliability of communication such as the multicastcommunication.

Further, the time division is performed on the transmissionacknowledgment request frame on the basis of the congestion degree ofthe communication of the transmission acknowledgment response frame.Here, if the number of STAs 20 serving as a target of communication suchas the multicast communication is increased, the frequency resources forthe transmission acknowledgment response are insufficient, and thus thenumber of STAs 20 in which the transmission acknowledgment is notperformed may increase. However, according to the present configuration,using the time division multiplexing in addition to the frequencydivision multiplexing, the wireless communication resources for thetransmission acknowledgment response are additionally secured, and thereliability of the multicast communication can be prevented from beinglowered due to the increase in the number of STAs 20.

Second Modified Example

As the second modified example of the present embodiment, thetransmission acknowledgment response frame may be a transmissionacknowledgment response frame for a multiplexed frame. Specifically, thetransmission acknowledgment response frame undergoes the frequencydivision multiplexing or includes a transmission acknowledgment responseframe for a frame which undergoes the space division multiplexing. Aprocess of the present modified example will be described in detail withreference to FIG. 11. FIG. 11 is a diagram for describing an example ofallocation of wireless communication resources of the AP 10 according tothe second modified example of the present embodiment.

Instead of transmission of data frames using a multicast method, the AP10 transmits a frame group which has undergone the space divisionmultiplexing and the frequency division multiplexing to the STA 20. Forexample, the AP 10 transmits data frames DATA#1 to DATA#4 which haveundergone the space division multiplexing and the frequency divisionmultiplexing illustrated in FIG. 11 to each of the STAs 20#1 to 20#4.Further, only the frequency division multiplexing or the space divisionmultiplexing may be performed on the data frames DATA#1 to DATA#4.

Then, the AP 10 transmits the transmission acknowledgment request framefor the multiplexed frame group to each of the STAs 20 of thetransmission acknowledgment target. For example, the AP 10 transmits theMBAR including the BAR information for each of the data frames DATA#1 toDATA#4. Instead of the MBAR frame, the BAR frame group obtained byperforming the frequency division multiplexing or the space divisionmultiplexing on the BAR#1 to BAR#4 frames for each of the data framesDATA#1 to DATA#4 may be transmitted. Further, in this case, each of thedata frames and each of the corresponding BAR frames may be connected(aggregated).

Then, the STA 20 which has received the transmission acknowledgmentrequest frame transmits the transmission acknowledgment response frameon the basis of the frequency allocation information included in thetransmission acknowledgment request frame. For example, the STAs 20#1 to20#4 transmits the BA#1 to BA#4 frames, and the BA#1 to BA#4 frames aresubjected to the frequency division multiplexing. Further, in a case inwhich the STA 20 supports the space division multiplex communication,the BA frame group may undergo the space division multiplexing.

As described above, according to the second modified example of thepresent embodiment, the transmission acknowledgment response frameincludes the transmission acknowledgment response frame for the framewhich has undergone the frequency division multiplexing or the spacedivision multiplexing. Therefore, it is possible to effectively use thewireless communication resources while improving the reliability ofcommunication even for the multiplex communication.

3. APPLICATION EXAMPLE

The technology according to the present disclosure can be applied tovarious products. For example, the communication device 20 (that is, theSTA 20) may be realized as mobile terminals such as smartphones, tabletpersonal computers (PCs), notebook PCs, portable game terminals, ordigital cameras, fixed-type terminals such as television receivers,printers, digital scanners, or network storages, or car-mountedterminals such as car navigation devices. In addition, the STA 20 may berealized as terminals that perform machine to machine (M2M)communication (also referred to as machine type communication (MTC)terminals) such as smart meters, vending machines, remotely controlledmonitoring devices, or point of sale (POS) terminals. Furthermore, theSTA 20 may be wireless communication modules mounted in such terminals(for example, integrated circuit modules configured by one die).

On the other hand, for example, the communication device 10 (that is,the AP 10) may be realized as a wireless LAN access point (also referredto as a wireless base station) which has a router function or does nothave a router function. The AP 10 may be realized as a mobile wirelessLAN router. The AP 10 may also be a wireless communication module (forexample, an integrated circuit module configured with one die) mountedon such a device.

3-1. First Application Example

FIG. 12 is a block diagram illustrating an example of a schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure can be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an externally connected interface 904, acamera 906, a sensor 907, a microphone 908, a input device 909, adisplay device 910, a speaker 911, a wireless communication interface913, an antenna switch 914, an antenna 915, a bus 917, a battery 918,and an auxiliary controller 919.

The processor 901 may be, for example, a central processing unit (CPU)or a system on chip (SoC), and controls functions of an applicationlayer and other layers of the smartphone 900. The memory 902 includesrandom access memory (RAM) and read only memory (ROM), and stores dataand programs executed by the processor 901. The storage 903 can includea storage medium such as a semiconductor memory or a hard disk. Theexternally connected interface 904 is an interface for connecting anexternally attached device such as a memory card or a universal serialbus (USB) device to the smartphone 900.

The camera 906 has an image sensor, for example, a charge coupled device(CCD) or a complementary metal oxide semiconductor (CMOS), to generatecaptured images. The sensor 907 can include a sensor group including,for example, a positioning sensor, a gyro sensor, a geomagnetic sensor,an acceleration sensor, and the like. The microphone 908 converts soundsinput to the smartphone 900 into audio signals. The input device 909includes, for example, a touch sensor that detects touches on a screenof the display device 910, a key pad, a keyboard, buttons, switches, andthe like, to receive operation or information input from a user. Thedisplay device 910 has a screen such as a liquid crystal display (LCD),or an organic light emitting diode (OLED) display to display outputimages of the smartphone 900. The speaker 911 converts audio signalsoutput from the smartphone 900 into sounds.

The wireless communication interface 913 supports one or more wirelessLAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad, toestablish wireless communication. The wireless communication interface913 can communicate with another device via a wireless LAN access pointin an infrastructure mode. In addition, the wireless communicationinterface 913 can directly communicate with another device in a directcommunication mode such as an ad hoc mode or Wi-Fi Direct (registeredtrademark). Note that, Wi-Fi Direct is different from the ad hoc mode.One of two terminals operates as an access point, and communication isperformed directly between the terminals. The wireless communicationinterface 913 can typically include a baseband processor, a radiofrequency (RF) circuit, a power amplifier, and the like. The wirelesscommunication interface 913 may be a one-chip module on which a memorythat stores a communication control program, a processor that executesthe program, and a relevant circuit are integrated. The wirelesscommunication interface 913 may support another kind of wirelesscommunication scheme such as a cellular communication scheme, anear-field communication scheme, or a proximity wireless communicationscheme in addition to the wireless LAN scheme. The antenna switch 914switches a connection destination of the antenna 915 among a pluralityof circuits (for example, circuits for different wireless communicationschemes) included in the wireless communication interface 913. Theantenna 915 has a single or a plurality of antenna elements (forexample, a plurality of antenna elements constituting a MIMO antenna),and is used for transmission and reception of wireless signals from thewireless communication interface 913.

Note that the smartphone 900 may include a plurality of antennas (forexample, antennas for a wireless LAN or antennas for a proximitywireless communication scheme, or the like), without being limited tothe example of FIG. 12. In this case, the antenna switch 914 may beomitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the externally connected interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 913, and the auxiliarycontroller 919 with each other. The battery 918 supplies electric powerto each of the blocks of the smartphone 900 illustrated in FIG. 13 viapower supply lines partially indicated by dashed lines in the drawing.The auxiliary controller 919 causes, for example, necessary minimumfunctions of the smartphone 900 to be operated in a sleep mode.

The data processing unit 11, the wireless communication unit 12, thecontrol unit 13, and the storage unit 14 described with reference toFIG. 4 may be implemented by the wireless communication interface 913 inthe smartphone 900 illustrated in FIG. 12. In addition, at least a partof these functions may be implemented by the processor 901 or theauxiliary controller 919. Further, at least some of the functions may beimplemented in the processor 901 or the auxiliary controller 919. Forexample, when the control unit 13 causes the wireless communication unit12 to set the transmission frequency on the basis of the frequencyallocation information included in the received MBAR frame, it ispossible to perform transmission and reception of the transmissionacknowledgment response frame using the frequency division multipleaccess in the communication such as the multicast communication.Accordingly, it is possible to achieve both the improvement in thereliability of communication such as the multicast communication and theeffective use of the wireless communication resources.

Note that the smartphone 900 may operate as a wireless access point(software AP) as the processor 901 executes the function of an accesspoint at an application level. In addition, the wireless communicationinterface 913 may have the function of a wireless access point.

3-2. Second Application Example

FIG. 13 is a block diagram illustrating an example of a schematicconfiguration of a car navigation device 920 to which the technology ofthe present disclosure can be applied. The car navigation device 920includes a processor 921, a memory 922, a Global Positioning System(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a wireless communication interface 933, anantenna switch 934, an antenna 935, and a battery 938.

The processor 921 may be, for example, a CPU or an SoC controlling anavigation function and other functions of the car navigation device920. The memory 922 includes RAM and ROM storing data and programsexecuted by the processor 921.

The GPS module 924 measures a position of the car navigation device 920(for example, latitude, longitude, and altitude) using GPS signalsreceived from a GPS satellite. The sensor 925 can include a sensor groupincluding, for example, a gyro sensor, a geomagnetic sensor, abarometric sensor, and the like. The data interface 926 is connectedwith an in-vehicle network 941 via, for example, a terminal (notillustrated) to acquire data generated on the vehicle side such as carspeed data.

The content player 927 reproduces content stored in a storage medium(for example, a CD or a DVD) inserted into the storage medium interface928. The input device 929 includes, for example, a touch sensor thatdetects touches on a screen of the display device 930, buttons,switches, and the like to receive operation or information input from auser. The display device 930 has a screen such as an LCD or an OLEDdisplay to display images of the navigation function or reproducedcontent. The speaker 931 outputs sounds of the navigation function orreproduced content.

The wireless communication interface 933 supports one or more wirelessLAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad, to executewireless communication. The wireless communication interface 933 cancommunicate with another device via a wireless LAN access point in theinfrastructure mode. In addition, the wireless communication interface933 can directly communicate with another device in a directcommunication mode such as an ad hoc mode or Wi-Fi Direct. The wirelesscommunication interface 933 can typically have a baseband processor, anRF circuit, a power amplifier, and the like. The wireless communicationinterface 933 may be a one-chip module on which a memory that stores acommunication control program, a processor that executes the program,and a relevant circuit are integrated. The wireless communicationinterface 933 may support another kind of wireless communication schemesuch as a near-field communication scheme, a proximity wirelesscommunication scheme, or the cellular communication scheme in additionto the wireless LAN scheme. The antenna switch 934 switches a connectiondestination of the antenna 935 among a plurality of circuits included inthe wireless communication interface 933. The antenna 935 has a singleor a plurality of antenna elements and is used for transmission andreception of wireless signals from and to the wireless communicationinterface 933.

Note that the car navigation device 920 may include a plurality ofantennas, without being limited to the example of FIG. 13. In this case,the antenna switch 934 may be omitted from the configuration of the carnavigation device 920.

The battery 938 supplies electric power to each of the blocks of the carnavigation device 920 illustrated in FIG. 14 via power supply linespartially indicated by dashed lines in the drawing. In addition, thebattery 938 accumulates electric power supplied from the vehicle side.

The data processing unit 11, the wireless communication unit 12, thecontrol unit 13, and the storage unit 14 described with reference toFIG. 4 may be implemented by the wireless communication interface 933 inthe car navigation device 920 illustrated in FIG. 13. In addition, atleast a part of these functions may be implemented by the processor 921.Further, at least some of the functions may be implemented in theprocessor 901 or the auxiliary controller 919. For example, when thecontrol unit 13 causes the wireless communication unit 12 to set thetransmission frequency on the basis of the frequency allocationinformation included in the received MBAR frame, it is possible toperform transmission and reception of the transmission acknowledgmentresponse frame using the frequency division multiple access in thecommunication such as the multicast communication. Accordingly, it ispossible to achieve both the improvement in the reliability ofcommunication such as the multicast communication and the effective useof the wireless communication resources.

Further, the wireless communication interface 933 may operate as the AP10 and may provide a wireless connection to a terminal owned by a userriding the vehicle. At this time, for example, when the control unit 13transmits the MBAR frame through the data processing unit 11 and thewireless communication unit 12, it is possible to perform transmissionand reception of the transmission acknowledgment response frame usingthe frequency division multiple access in the communication such as themulticast communication. Accordingly, it is possible to achieve both theimprovement in the reliability of communication such as the multicastcommunication and the effective use of the wireless communicationresources.

Further, the technology of the present disclosure may be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of theabove-described car navigation device 920, an in-vehicle network 941,and a vehicle-side module 942. The vehicle-side module 942 generatesvehicle-side data such as a vehicle speed, the number of enginerotations, or failure information and outputs the generated data to thein-vehicle network 941.

3-3. Third Application Example

FIG. 14 is a block diagram illustrating an example of a schematicconfiguration of a wireless access point 950 to which the technology ofthe present disclosure can be applied. The wireless access point 950includes a controller 951, a memory 952, an input device 954, a displaydevice 955, a network interface 957, a wireless communication interface963, an antenna switch 964, and an antenna 965.

The controller 951 may be, for example, a CPU or a digital signalprocessor (DSP) and operates various functions (for example, accesslimitation, routing, encryption, a fire wall, and log management) of theInternet Protocol (IP) layer and higher layers of the wireless accesspoint 950. The memory 952 includes RAM and ROM and stores a programexecuted by the controller 951 and various kinds of control data (forexample, a terminal list, a routing table, an encryption key, securitysettings, and a log).

The input device 954 includes, for example, a button or a switch, andreceives operation performed by a user. The display device 955 includesan LED lamp and displays an operation status of the wireless accesspoint 950.

The network interface 957 is a wired communication interface thatconnects the wireless access point 950 with a wired communicationnetwork 958. The network interface 957 may include a plurality ofconnection terminals. The wired communication network 958 may be a LANsuch as Ethernet (registered trademark) or may be a wide area network(WAN).

The wireless communication interface 963 supports one or more wirelessLAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad, to supplywireless connection to a nearby terminal as an access point. Thewireless communication interface 963 can typically include a basebandprocessor, an RF circuit, and a power amplifier. The wirelesscommunication interface 963 may be a one-chip module in which memorystoring a communication control program, a processor executing theprogram, and relevant circuits are integrated. The antenna switch 964switches a connection destination of the antenna 965 among a pluralityof circuits included in the wireless communication interface 963. Theantenna 965 includes one antenna element or a plurality of antennaelements and is used to transmit and receive a wireless signal throughthe wireless communication interface 963.

The data processing unit 11, the wireless communication unit 12, thecontrol unit 13, and the storage unit 14 described with reference toFIG. 4 may be implemented by the wireless communication interface 963 inthe wireless access point 950 illustrated in FIG. 14. In addition, atleast a part of these functions may be implemented by the controller951. For example, when the MBAR frame for the multicast frame or thelike is transmitted through the data processing unit 11 and the wirelesscommunication unit 12, it is possible to perform transmission andreception of the transmission acknowledgment response frame using thefrequency division multiple access in the communication such as themulticast communication. Accordingly, it is possible to achieve both theimprovement in the reliability of communication such as the multicastcommunication and the effective use of the wireless communicationresources.

4. CONCLUSION

As described above, according to one embodiment of the presentdisclosure, the transmission acknowledgment response related to thecommunication in which a frame is transmitted to a plurality ofdestinations is performed using the frequency division multiplexcommunication, and thus it is possible to effectively use the wirelesscommunication resources as compared with the case in which thecommunication for the transmission acknowledgment response ischronologically performed while improving the reliability of thecommunication.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

For example, in the above embodiment, both the primary channelinformation and the bandwidth information are included in thetransmission acknowledgment request frame, that is, the BAR information,but the present technology is not limited to this example. For example,only the primary channel information may be included in the transmissionacknowledgment request frame. For example, in a case in which thebandwidth allocated to the STA 20 is known to the STA 20, only thecenter frequency field is set in the Channel Info of the MBAR frame, andonly the primary channel information is stored. In this case, the dataamount of the transmission acknowledgment request frame is reduced to besmaller than the case in which the bandwidth information is included inthe transmission acknowledgment request frame, and thus it is possibleto reduce the communication amount and effectively use the wirelesscommunication resources.

Similarly, in a case in which the center frequency allocated to the STA20 is known to the STA 20, only the bandwidth information may beincluded in the BAR information. Further, in a case in which thetransmission time of each STA 20 is known to the STA 20, thetransmission acknowledgment request frame not including transmissiontime information may be transmitted. Further, of course, in a case inwhich both the center frequency and the bandwidth are known to the STA20, only the transmission time may be included in the BAR information.

Further, in the above embodiment, the example in which the primarychannel information is the information indicating the center frequencyor the information for the calculation formula has been described, butthe primary channel information may be the information indicating thechannel number. In this case, the STA 20 specifies the center frequencyfrom the channel number indicated by the primary channel information.

Further, in the above embodiment, the example in which the BARinformation field of the transmission acknowledgment request frame isincluded in the portion corresponding to the payload has been described,but the BAR information field may be included in the PHY header or theMAC header.

Further, in the above embodiment, the example in which the transmissionacknowledgment request frame is transmitted using the multicast schemeor the frame multiplexing scheme has been described, but thetransmission acknowledgment request frame may be transmitted as a framein which the BAR frames addressed to the STAs 20 of the transmissionacknowledgment target are aggregated.

Further, in the above embodiment, the example in which the transmissionacknowledgment response frame or the transmission acknowledgment requestframe undergoes the frequency division multiplexing or the spacedivision multiplexing has been described, but other frames may undergothe frequency division multiplexing or the space division multiplexing.For example, the BAR frame group and the data frame illustrated in FIG.11 may undergo the frequency division multiplexing or the space divisionmultiplexing using a frequency or a spatial stream which is empty.

Further, in the above embodiment, for the sake of description, theexample in which there is an empty band in FIG. 6 has been described,but it is desirable to allocate the wireless communication resources sothat there is no empty band as illustrated in FIG. 5 in order toeffectively use the wireless communication resources.

In the above embodiment, the example in which the bandwidth used for thecommunication in FIGS. 5, 6, 10, and 11 is 80 MHz or 40 MHz has beendescribed, but the bandwidth may be larger or smaller.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1)

A communication device, including:

a communication unit configured to perform communication of a frame,

in which the communication unit

-   -   transmits a transmission acknowledgment request frame for a        transmission acknowledgment response frame including frequency        allocation information specifying a transmission frequency of        the transmission acknowledgment response frame, and    -   receives the transmission acknowledgment response frame which        has undergone frequency division multiplexing, on the basis of        the frequency allocation information.        (2)

The communication device according to (1),

in which the transmission acknowledgment response frame is transmittedthrough the transmission frequency specified from the frequencyallocation information.

(3)

The communication device according to (1) or (2),

in which the transmission acknowledgment response frame includes atransmission acknowledgment response frame for a multicast frame.

(4)

The communication device according to any one of (1) to (3),

in which the transmission acknowledgment response frame includes atransmission acknowledgment response frame for a frame which hasundergone frequency division multiplexing or space divisionmultiplexing.

(5)

The communication device according to any one of (1) to (4),

in which the transmission acknowledgment request frame is connected to aframe which is a transmission acknowledgment target.

(6)

The communication device according to any one of (1) to (5),

in which the transmission acknowledgment request frame further includestransmission time information specifying a transmission time of thetransmission acknowledgment response frame, and

the communication unit receives the transmission acknowledgment responseframe which has undergone time division, on the basis of thetransmission time information.

(7)

The communication device according to any one of (1) to (6),

in which the transmission acknowledgment request frame includes responsedevice information specifying the communication device which isrequested to transmit the transmission acknowledgment response frame,and

the communication unit receives the transmission acknowledgment responseframe from the communication device specified on the basis of theresponse device information.

(8)

The communication device according to any one of (1) to (7),

in which the frequency allocation information includes informationspecifying a center frequency of the transmission frequency.

(9)

The communication device according to (8),

in which the center frequency differs in accordance with respectivedestinations of the transmission acknowledgment request frametransmitted in a same period.

(10)

The communication device according to (8) or (9),

in which the center frequency is specified on the basis of at least oneof identification information for a destination of the transmissionacknowledgment request frame and time information of the own device.

(11)

The communication device according to any one of (8) to (10),

in which the center frequency differs from a center frequency of a framewhich is a transmission acknowledgment target.

(12)

The communication device according to any one of (8) to (11),

in which the frequency allocation information includes informationspecifying a bandwidth of the transmission frequency.

(13)

The communication device according to (12),

in which the bandwidths are different between at least some ofdestinations of the transmission acknowledgment request frame.

(14)

The communication device according to (12) or (13),

in which the bandwidth used for transmission of the transmissionacknowledgment request frame in a same period is different from abandwidth of a frame which is a transmission acknowledgment target.

(15)

A communication device, including:

a communication unit configured to perform communication of a frame,

in which the communication unit

-   -   receives a transmission acknowledgment request frame for a        transmission acknowledgment response frame including frequency        allocation information specifying a transmission frequency of        the transmission acknowledgment response frame, and    -   transmits the transmission acknowledgment response frame on the        basis of the frequency allocation information, and

the transmission acknowledgment response frame undergoes frequencydivision multiplexing.

(16)

The communication device according to (15),

in which the communication unit transmits the transmissionacknowledgment response frame through the transmission frequencyspecified from the frequency allocation information.

(17)

The communication device according to (15) or (16),

in which the transmission acknowledgment request frame further includestransmission time information specifying a transmission time of thetransmission acknowledgment response frame,

the communication unit transmits the transmission acknowledgmentresponse frame at the transmission time specified from the transmissiontime information, and

the transmission acknowledgment response frame undergoes time division.

(18)

The communication device according to any one of (15) to (17),

in which the transmission acknowledgment request frame includes responsedevice information specifying the communication device which isrequested to transmit the transmission acknowledgment response frame,and

the communication unit transmits the transmission acknowledgmentresponse frame in a case in which the own device is the communicationdevice specified from the response device information.

(19)

A communication method, including:

transmitting, by a communication unit configured to performcommunication of a frame, a transmission acknowledgment request framefor a transmission acknowledgment response frame including frequencyallocation information specifying a transmission frequency of thetransmission acknowledgment response frame; and

receiving the transmission acknowledgment response frame which hasundergone frequency division multiplexing, on the basis of the frequencyallocation information.

(20)

A communication method, including:

receiving, by a communication unit configured to perform communicationof a frame, a transmission acknowledgment request frame for atransmission acknowledgment response frame including frequencyallocation information specifying a transmission frequency of thetransmission acknowledgment response frame; and

transmitting the transmission acknowledgment response frame on the basisof the frequency allocation information,

in which the transmission acknowledgment response frame undergoesfrequency division multiplexing.

REFERENCE SIGNS LIST

-   10 communication device, AP-   11 data processing unit-   12 wireless communication unit-   13 control unit-   14 storage unit-   20 communication device, STA

1: A communication device, comprising: one or more circuits configuredto perform communication of a frame, wherein the one or more circuitsare configured to transmit a transmission acknowledgment request framefor a transmission acknowledgment response frame including frequencyallocation information specifying a transmission frequency of thetransmission acknowledgment response frame, and receive the transmissionacknowledgment response frame which has undergone frequency divisionmultiplexing, on the basis of the frequency allocation information,wherein the delivery acknowledgement request frame being transmitted toone or a subset of devices that is selected to reply with thetransmission acknowledgement response frame, and wherein the frequencyallocation information includes information specifying a bandwidth ofthe transmission frequency.